<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <script>
        document.write(parseInt("125ff652"))
        //找到第一个数字进行转换
        let str = "for(let i = 0;i<10;i++){document.write('<p>dddddd</p>')}"
        eval(str)
        //运行字符串代码

        let falg = isNaN("a100")
        eval(document.write(falg))
        //判断是不是数字  true：不是数字  false：是数字
    </script>
</body>
</html>
